\begin{tikzpicture}
	\pgfmathsetmacro{\a}{1.0}
	\pgfmathsetmacro{\b}{1.5}
	\pgfmathsetmacro{\c}{2.0}
	\pgfmathsetmacro{\xc}{\c/2}

	\tkzDefPoints{0/0/A, 0/0.1/pa, \a/0/E, \a+\a/0/B, \a+\a+\b/0/C, \a+\a+\b-\xc/0/D, \a+\a+\b+0.5/0/M}
	\tkzDrawSegment(A,M)
	\tkzDrawSegment(A,pa)
	\tkzLabelPoints[above=0.3em](A)
	\tkzLabelPoints[above](M)

	\tkzDrawSegments[dim={$a$,-1em,}](A,E)
	\tkzDrawSegments[dim={$a$,-1em,}](E,B)
	\tkzLabelPoints[above=0.3em](B)
\end{tikzpicture}

